Box on Cart (Friction)

It asks what tension on the rope would give the cart a maximum acceleration. The surface the cart is on is frictionless, while the cart itself is not (the surface the box is on).

To solve this, I figured that pulling the rope with a force of usN would give the maximum acceleration of the cart. However, this seems too easy; I think I may have not completely answered the question.

Staff: Mentor

Instead, think this way: What's the only force directly applied to the cart? What's the maximum acceleration acceleration that that force can give the cart? Use that to find the required tension in the rope.

Staff: Mentor

You really didn't provide your reasoning, just your answer. (No, it's not correct.)
Instead, think this way: What's the only force directly applied to the cart? What's the maximum acceleration acceleration that that force can give the cart? Use that to find the required tension in the rope.